Optical universal serial bus (USB)

ABSTRACT

Embodiments of the invention are directed to an optical USB (OUSB) to enhance the data rate of USB by adding super-high data rate (e.g. 10 Gbps) optical communication on top of its current specification so that backward compatibility is achievable. Mechanical tolerances may be achieved by using embedded lenses to expand a beam emerging from the connector prior to entering its mating connector and using an identical lens in the mating connector to collimate the beam back onto a fiber.

FIELD OF THE INVENTION

Embodiments of the invention relate to the universal serial bus and, more particularly, to a USB including having optical capabilities.

BACKGROUND INFORMATION

In many of today's processing systems, such as personal computer (PC) systems, there exist universal serial bus (USB) ports for connecting various USB devices. Some of these USB devices are frequently used by PC users. For example, these USB devices may be printers, compact disk read-only-memory (CD-ROM) drives, CD-ROM Writer (CDRW) drives, digital versatile disk (DVD) drives, cameras, pointing devices (e.g., computer mouse), keyboards, joy-sticks, hard-drives, speakers, etc. Some of these devices use more of the available USB bandwidth than others. For example, a USB CDRW is a high bandwidth device, while human interface devices (HID), such as computer mice, keyboards and joysticks, are low bandwidth devices.

Within a USB cable there are typically four shielded wires. Two of the wires may provide power (+5 volts (red) and ground (brown)) and a twisted pair (blue and yellow) for data.

At either end of a USB cable there is a standard sized connector. These connectors each has a different profile designated “A” connectors and “B” connectors. More recently, mini versions of these connectors are appearing to accommodate smaller devices. “A” connectors head “upstream” toward the computer. On the other end, “B” connectors head “downstream” and connect to individual devices. This way, it is almost fool proof to make a wrong connection.

The USB standard allows for low power devices (e.g., mice, memory sticks, keyboards, etc.) to draw their power from their USB connection. Larger devices requiring more power, such as scanners or printers, typically have their own dedicated power supply.

FIG. 1 shows a typical USB “A” male connector 10. The cable 12, comprises the above mentioned four wires and connects to a plastic housing 14. Each of the four wires electrically connects within the housing 14 to one of four contact terminals or pins 16 mounted on the top side of an insulative base 18. The insulative base 18 is wrapped in a metal shield 19. Openings 20 in the metal shield may be provided to lock the connector in place when plugged into a corresponding female connector.

FIG. 2 shows a more detailed view of the insulative base 18. As shown, conductive fasteners 21, 22, 23, and 24 are provided at one end to connect to each of the four wires in the cable 12. The outer two fasteners 21 and 22, are for power and the inner two connectors 23 and 24 are for data. On a top side of the insulative base 18 are four pins 31, 32, 33, and 34, corresponding to the contacts 21, 22, 23, and 24, respectively. The pins 31-34 within the male connector 10 electrically engage to mating pins within the female connector when plugged in.

Different standards of USB technology have different bandwidths. For instance, Universal Serial Bus Specification, revision 1.1, Sep. 23, 1998 (USB 1.1) devices are capable of operating at 12 Mbits/second (Mbps). Universal Serial Bus Specification, revision 2.0, Apr. 27, 2000 (USB 2.0; also known as high-speed USB) devices are capable of operating at 480 Mbps. However, as technology progresses engineers are constantly striving to increase operating speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a typical USB “A” male connector;

FIG. 2 is a block diagram showing a more detailed view of the insulative base of a USB “A” male connector;

FIG. 3 is a top view of an insulative base of a USB “A” male connector according to embodiments of the invention;

FIG. 4 is a bottom view of an insulative base of a USB “A” male connector according to embodiments of the invention;

FIG. 5 is a block diagram of a female USB “A” connector according to embodiments of the invention; and

FIG. 6 is a cross sectional view of a mated USB “A” connector according to embodiments of the invention.

DETAILED DESCRIPTION

Embodiments of the invention are directed to an optical USB (called OUSB hereafter) to enhance the data rate of USB by adding super-high data rate (e.g. 10 Gbps) optical communication on top of its current specification so that backward compatibility is achievable.

A challenge with OUSB is the need to be backward compatible with the legacy USB form factor, which requires relatively large mechanical tolerances. That is, the mechanical tolerance specified by the USB connector is 0.3 mm. Optical connectors typically use a butt contact approach. However, optical butt contact may require 10 um precision or better. This makes the usual optical connector an unviable solution for USB form factor.

In order to resolve this issue, embodiments disclose an optical beam expanding approach. By expanding the beam size to, for example, 1 mm, the 0.3 mm mechanical tolerance required by the USB connector may be achieved.

Referring now to FIGS. 3 and 4, there is shown a top view and a bottom view, respectively, of the insulative base 18 of an OUSB connector according to one embodiment of the invention. Similar to that which is shown and described in FIG. 2, conductive fasteners 21, 22, 23, and 24 are provided at one end to connect to each of the four wires in the cable 12. The outer two fasteners 21 and 22, are for power and the inner two connectors 23 and 24 are for data. On a top side of the insulative base 18 are four pins 31, 32, 33, and 34, corresponding to the contacts 21, 22, 23, and 24, respectively. The pins 31-34 within the male connector 10 electrically engage to mating pins within the female connector when plugged in.

In addition, the OUSB connector comprises embedded lenses 40, 41, 42, and 43 on the leading edge of the insulative base 18. These lenses are optically coupled to respective fibers 50, 51, 52, and 53 for providing high speed optical data throughput. While four lenses are shown, this is by way of example and more or fewer may be provided. The lenses 40-43 may be within tapered holes as shown for fiber self-alignment in installation. The tapered holes may have metal inserts for added rigidity. While not shown in FIGS. 3 and 4, the insulative base 18 would be contained in a plastic housing 14 and include a metal shield 19 as shown in FIG. 1.

FIG. 5 shows the inside of an “A” connector female OUSB configured to mate with the connector shown in FIGS. 3 and 4. As in standard USB, an insulative carrier 50 may comprise four contacts 51, 52, 53, and 54, which may be spring loaded, adapted to make electrical connection with pins 31, 32, 33, and 34, respectively, in the male connector. The four contacts 51, 52, 53, and 54 may be in turn electrically connected to a USB device with contact posts 61, 62, 63, and 64. Four fibers 70, 71, 72, and 73 may enter the female connector and be optically coupled to four embedded lenses 80, 81, 82, and 83, which, when connected, optically couple to the corresponding lenses 40-43 in the male connector.

FIG. 6 shows a cut-away side view of a male OUSB connector 88 and female OUSB connector 90 when mated. For simplicity, the electrical connections are not shown in this figure, but may be present as shown in FIGS. 3-5. The male OUSB connector 88 comprises a plastic base or core 91. The female OUSB connector also comprises a plastic core 92 each surrounded by its own metal shield 93. The plastic cores 91 and 92 may include V-grooves 95 to facilitate alignment of optical fibers 94 and 95.

After the plug (male) 90 and receptacle (female) 88 are mated, the lenses 43 and 80 are used to expanded the optical beam to facilitate optical communication. As illustrated, the optical beam from the fiber 94 from the male side may be expanded by lens 43 to, for example, approximately 1 mm. The expanded beam may then be collimated by the embedded lens 80 at the female side couple with fiber 95. Since the embedded lens profile 43 and 80 is identical at both sides, optical signals can go either direction. As one can see, expansion of the beam makes it possible to optically couple the fibers 94 and 95 since traditional butt coupling does not work well within the mechanical tolerance confines of USB connectors.

While the above embodiments have been illustrated as USB “A” connectors one skilled in the art will readily recognize that the invention described herein is equally applicable to USB “B” connectors or other USB form factors.

There are many advantages to OUSB. In particular, embodiments maintain all traditional USB electrical connections within the existing USB form factor. Thus, it is fully backward compatibility with the USB 2.0 specification. It allow super-high speed data rate (i.e. 10 Gbps) compared to the high speed of USB 2.0 (480 Mbps). In addition, optical signal integrity may be maintained in high EMI environments such as factories where traditional electrical connections may experience issues.

The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize.

These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation. 

1. A universal serial bus (USB) connector, comprising: an insulative base having a top surface and a leading edge; a plurality of pins on the top surface of the insulative base to make electrical connections; and at least one embedded lens on the leading edge of the insulative base to provide optical function.
 2. The USB connector as recited in claim 1, further comprising: at least one fiber optically coupled to the at least one embedded lens.
 3. The USB connector as recited in claim 2 wherein the embedded lens expands a beam emerging from the fiber.
 4. The USB connector as recited in claim 3 wherein the embedded lens expands the beam to approximately 1 mm.
 5. The USB connector as recited in claim 2 wherein the embedded lens collimates a beam into the fiber.
 6. The USB connector as recited in claim 2 further comprising: four embedded lenses each respectively optically coupled to four fibers.
 7. The USB connector as recited in claim 1, further comprising: a mating connector comprising at least one embedded lens to optically couple to the at least one embedded lens on the leading edge of the insulative base when mated.
 8. The USB connector as recited in claim 7 wherein the embedded lens of the mating connector is identical to the at least one embedded lens on the leading edge of the insulative base.
 9. A method of providing optical function to a USB connector, comprising: providing an insulative base having a top surface and a leading edge; positioning a plurality of pins on the top surface of the insulative base to make electrical connections; and embedding at least one lens on the leading edge of the insulative base for optical communication.
 10. The method as recited in claim 9 further comprising: expanding a beam emerging from a fiber with the embedded lens to approximately 1 mm.
 11. The method as recited in claim 9, further comprising: collimating a beam onto a fiber with the embedded lens.
 12. The method as recited in claim 9 further comprising: providing a plurality of embedded lenses on the leading edge of the insulative base.
 13. The method as recited in claim 9 further comprising: plugging the USB connector into a mating connector to optically couple the embedded lens to a corresponding lens in the mating connector.
 14. The method as recited in claim 9 wherein the embedded lens and the corresponding lens in the mating connector are identical.
 15. An optical universal serial bus (OUSB), comprising: a universal serial bus (USB) connector comprising four electrical connections mounted to a top surface of an insulative base; a plurality of embedded lenses on a leading edge of the insulative base; a plurality of fibers each optically coupled to a respective one of the plurality of embedded lenses; wherein each lens expands a beam traveling in a first direction from an optical fiber and collimates a beam traveling in a second direction onto the optical fiber to meet USB mechanical tolerances.
 16. The OUSB as recited in claim 15 wherein the OUSB is backward compatible with USB.
 17. The OUSB as recited in claim 15 further comprising four embedded lenses on the leading edge of the insulative base.
 18. The OUSB as recited in claim 15 further comprising: V-grooves in the insulative base to facilitate alignment of the fibers.
 19. The OUSB as recited in claim 15 further comprising; a mating OUSB connector having identical embedded lenses optically aligned with the plurality of embedded lenses on a leading edge of the insulative base when mated.
 20. The OUSB as recited in claim 15 wherein the beam is expanded to approximately 1 mm. 